When multiple output drivers switch simultaneously, they induce a voltage change in the power distribution network of an electronic device. The voltage change provides a noise coupling path between output drivers on the electronic device. Other mechanisms for noise coupling between drivers include mutual inductance and mutual capacitance between signals in the device package or between signal vias in the breakout region of a printed circuit board. These types of coupled noise are known as Simultaneous Switching Noise (SSN).
SSN can be defined as a noise voltage induced on a victim Input/Output (I/O) pin of an electronic device due to the switching behavior of other aggressor I/O pins in the device. A victim pin is defined as an I/O pin that has noise induced on it, whereas an aggressor pin is an I/O pin that induces noise. SSN can cause logic circuits to switch state falsely, if it is uncontrolled and signal integrity issues have significant effects on the performance of high-speed digital systems. SSN can also cause problems in signal timing and quality such as signal degradation in rising time, signal channel transmission delay skew, and increase in signal overshoot.
With the advent of Complementary Metal-Oxide-Semiconductor (CMOS) technology, electronic devices can now use large numbers of I/O interfaces. One of the techniques of lowering the power consumption of these I/O interfaces is by voltage reduction. When voltage is reduced, the noise margin of these I/O interfaces become smaller, thus it is essential to mitigate or optimize the amount of SSN of these interfaces to prevent the SSN from excessively reducing the available noise margin.
An SSN optimization mechanism generally requires some form of feedback to gauge the effectiveness of a proposed optimization. Existing tools for calculating SSN may provide graphical means for visually representing the SSN amount. However, many of these tools do not provide the means for SSN optimization. Current methods of SSN optimization are often performed without any feedback mechanism, thus making it difficult to evaluate the effectiveness of the optimization.
It is in this context that embodiments of the invention arise.